CAPACITIES (BTU'S NAT. GAS) MINIMUM MAXIMUM
  A B C D E WEIGHT (1") (2 LBS)  
ER-0 3/8" 3/8" 5-13/16" 2-11/16" 1-5/8" 1 2,400 20,500  
ER-1 3/8" 1/2" 7-3/8" 2-13/16" 2-13/16" 1 3,200 33,000  
ER-2 3/8" 3/4" 7-3/4" 2-13/16" 2-13/16" 1-1/2 5,200 48,400  
ER-3 1/2" 1" 9-1/16" 2-13/16" 2-13/16" 1-3/4 7,100 87,400  
ER-4S 3/8" 1"-1/4" 8-3/4" 2-3/4" 2-7/8" 1-1/2 13,000 149,000  
ER-4 3/4" 1"-1/4" 11-13/16"   3-1/2" 4-1/8 3-1/2 13,000 149,000
ER-5 3/4" 1"-1/2" 14" 3-1/2" 4-1/8" 4-1/2 22,000 249,000  
ER-6 1" 2" 17-1/2" 3-11/16" 4-1/8" 7 35,000 431,000  
ER-7 1"-1/4" 2"-1/2" 22-5/8" 4-1/8" 5" 12 56,000 657,000